Optical apparatus for examining cavities and tubes in the body



July 3, 1928.

G. LOECK OPTICAL APPARATUS FOR EXAMINING CAVITIES AND TUBES IN THE BODYFiled March 26, 1927 nhilnlllinnlluulfl .linllxipyll! Patented July 3,19 28.

UNITED STATES PATENT OFFICE.

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OPTICAL APPARATUS FOR MINING CAVITIES AND TUBES IN THE BODY. 1 I

Application fled larch 26, 1927, serial No. 178,787, aad in Germanylarch 30, 1926.

The light filters of optical apparatus for examining cavities and tubesin the body (e. g. of cystoscopes and gastroscopes) have hitherto beenconstructed in various ways.

One has, for instance, used plane-parallel,

coloured glass plates as filters or dyed layers of gelatine applied toglass, or one has also .constructed single lenses as filters byimparting to them a corresponding colour.

According to thepresent invention one uses as filters layers of cementof cemented members of the optical system. This kind of filtering hasthe advantagethat it does not I uire any' special optical elementbecause t e optical apparatus concerned, unless they are to be too1mperfect,-are e. g. always provided with cemented; lenses, so that itis only necessary to use a correspondingly dyed cement instead of thecolourless cement hitherto used. Besides, these filters are ex- 'emptfrom the drawback-peculiar to coloured lenses, viz, that thefilteringlayer varies in thickness at different places.

The annexed drawing shows as a construcelements, adapted to present tothe observer an image of the; art to be examined, at least one of thesee ements consisting of two lenses, united by means of dyed cement.

GUNTHER LoEcK.

